Work machines are commonly used in the agricultural, construction, and forestry related industries. For example, motor graders employ large blades that may be used for finish grading of a flat surface, such as for a roadway or a parking lot, that may have been rough graded by a bulldozer or scraper. Typical graders have a rear drive train with two axles, and may also have a hydraulic front wheel drive system, with the blade being located between the front wheels and the operator cab, and with the rear drive train axles being located under or aft of the operator cab. An internal combustion engine, such as a diesel engine, typically provides power for both the drive train and for hydraulic system loads, such as the hydraulic front wheel drive and a hydraulic cooling fan. During normal operations of the work machine, the hydraulic loads may vary significantly in a manner not readily predicted, for example, changing as a function of how the work machine is being used and the environment it is operating in. The variation in hydraulic load may adversely affect the power delivered from the engine to the rear drive train, particularly when operating the work machine near the maximum limits established for the engine, and hence adversely affect the operability of the machine.
Notwithstanding advances in the art, there is a still a need for a system and method for controlling an engine in a work machine that may compensate for varying hydraulic loads.